1. Field of the Invention
The present invention relates to improvements in devices and methods for the distribution of seasoning materials onto snack foods and the like during the snack food manufacturing process. In particular, the invention provides improvements permitting uniform distribution of a variety of seasoning materials (or "toppings") during the manufacture of snack food items.
2. Description of the Background Art
Many commercially available snack food items include seasonings or other toppings of one form or another deposited upon their surfaces. Examples of such snack foods include potato chips, which can be seasoned with salt, barbecue flavoring, sour cream and onion flavoring, cheese-based toppings, etc. Corn chips and other snack foods items, such as pretzels, corn puffs and popcorn, can be similarly seasoned. In addition to the savory snack food items just described, sweet snacks commonly are topped with powdered and granular sugars, decorative toppings and the like.
While powdered and granular toppings can be applied to snack food items in a variety of manners, a particularly efficient application method includes dispensing the topping onto snack food items which are tumbling in a rotating drum. The tumbling action of the snack food items aids in the even distribution of the topping over the entire contents of the drum. Where the application of a seasoning topping is merely one step in a continuous process for the manufacture of the snack food, it is known to tie the operation of the topping dispenser to the operation of the production line; thus, the topping should be dispensed only while the product is moving along the production line, for example when travelling through and tumbling within the rotating drum.
The commonly used savory snack food seasonings and toppings exhibit a variety of physical properties which govern their behavior during the dispensing operation. "Flour salt," the finely powdered salt used as a topping for potato chips, is extremely dry and free-flowing. Thus, this topping tends to rapidly pass through dispensing equipment, and its flow must be carefully metered and regulated to avoid over-salting the snack food product. Sour cream and onion toppings (as well as cheese-based toppings, and dairy-based and oil-based toppings in general), are relatively moist and tend to resist free flow through dispensing equipment. These relatively "clumpy" or "sticky" toppings tend to clog dispensing apparatus and are prone to intermittent, uneven flow.
Thus, it will be apparent that one important attribute of a topping dispensing apparatus is the ability to dispense, in a controlled, evenly regulated manner, both free-flowing and sticky toppings.
The even distribution of seasoning toppings is important to many aspects of the snack food production process. First, even distribution is essential to providing a uniform appearing and tasting product. One aspect of building consumer loyalty is the ability to provide a uniform-tasting product both within any one given package, as well as over time. Further, uneven or wasteful topping dispensing can adversely impact the economy of the manufacturing process. Over-topped and under-topped items may need to be discarded to avoid inconsistencies in the final, packaged product.
It is known in the art to apply seasonings from a reservoir "hopper," through a metering tube and onto a snack product being tumbled in a rotating drum. For example, commonly owned U.S. Pat. No. 4,614,162 utilizes a tube inserted along the centerline of the tumbling chamber of a rotating drum, through which the seasoning is moved by means of an auger. The bottom of the tube has a series of holes therein, through which the seasoning falls onto snack product in the tumbling chamber. With certain seasonings, such as the dairy-based and oil-based "sticky" toppings described above, uniform seasoning dispersion along the length of the series of seasoning distribution holes is not attained. With these relatively flow-resistant toppings, an undue proportion of the topping passes past the exit holes and is expelled almost entirely from the distal end of the tube. With other seasonings, for example very free-flowing toppings such as flour salt, an undue proportion is expelled through the first few holes closest to the hopper, with very little of the topping reaching the holes at the distal end of the tube. Furthermore, due to the position of the seasoning distribution holes at the bottom of the tube, these free-flowing seasonings continue to fall from the tube after the auger has stopped, until all of the seasoning is drained from the tube onto the product below. When the operation of the auger is keyed to the operation of the entire production line, an undue amount of the topping is applied to the product which is parked beneath the tube. Frequently, this over-seasoned product must be discarded. This continued flow also results in a lag in seasoning distribution when the auger is restarted, and an attendant non-uniform distribution upon start-up.
There thus remains a need in the art for improvements in seasoning distribution devices and methods. Ideally, the distribution apparatus should provide even dispensing of seasoning materials along the entire length of the rotating product-tumbling drum with both very free-flowing and sticky toppings.